This has probably been asked already, but I think the AOO warning when you go to move out of a creature's range should be a bit more apparent. Much like when you walk through dangerous terrain, have the move line turn red, or some other blatantly apparent marking that will clearly show when you will be attacked due to moving out of range. Some creatures when trying to move around them, it doesn't look like you are moving out of range, but it's just enough and will trigger the attack.
Thanks!!